Researchers developing wheat resistant to mites, diseases

Sometimes the best defense is a good offense. Following that logic, researchers at Kansas State University are building a defense against pests and diseases that attack wheat by identifying plants that carry natural resistance to those pests and diseases with an eye toward developing varieties for Kansas that carry those resistance traits.

The wheat curl mite, known to scientists as Aceria tosichella Keifer, is a tiny, white pest, whose size belies its ability to wreak havoc through the diseases it carries into wheat fields. Many wheat varieties are well suited to grow in Kansas in other ways, but none are resistant to the wheat curl mite and the diseases it vectors -- Wheat Streak Mosaic Virus, Triticum Mosaic Virus and Wheat Mosaic Virus, formerly known as High Plains Virus, said K-State entomology professor, Mike Smith. He and a team of researchers are studying wheat varieties grown in other areas that naturally resist the mite and the viruses it carries.

“We have identified plants with resistance to the wheat curl mite and two of the diseases it carries – wheat streak mosaic virus and High Plains virus and have now developed what’s called an advanced breeding line, that will result in a new variety of wheat that carries resistance to the mite and those two viruses,” said Smith, who is a lead researcher on the project.

“This is not GMO wheat,” he said, referring to the practice of taking genes from one species and incorporating them into another, resulting in a genetically-modified organism. “This is done with genes that already exist in wheat. There is nothing transgenic or GMO about this.”

By developing varieties that resist pests and diseases, scientists can protect Kansas wheat, reduce or eliminate the need for pesticides, and increase producer profits, he said.

The project is funded by the Kansas Wheat Commission and Kansas Wheat Alliance.

Other K-State lead researchers involved are Wen-Po Chuang, post-doctoral research associate in entomology; Anna Whitfield, associate professor of plant pathology; and wheat breeder Allan Fritz, professor of agronomy. Scientists at Oklahoma State University, the University of Nebraska, and Texas A&M University are cooperating on the project.

At stake in Kansas alone, is a crop with a cash value of $2.9 billion (2012), according to Kansas Wheat. The cash value of Kansas wheat exports (sold outside the U.S.) was $1.5 billion.

“There is no chemical control for the curl mite or any of these viruses,” Smith said. “With no control, Kansas producers are losing $20 million to $30 million a year due to these mites and viruses.”

“There are lines in other states that have resistance to the mite or resistance to some of the viruses, but not both,” Smith said. “This is a unique line that we’re developing.”

“We are using the mite- and virus-resistant plants in crosses that will be submitted to HPI to make doubled haploids,” said Fritz, who added that doubled haploids involve a new technique that allows researchers to cut time for development of a variety from 11 years to six or seven years. He referred to Heartland Plant Innovations, a collaboration of Kansas Wheat, Kansas State University, the University of Kansas, and private investors, working to develop technologies for gene discovery, trait validation and crop improvement.

“That will allow us to rapidly combine the resistances with other traits, such as more durable resistance to the rust diseases. It's an important step toward delivering varieties that protect producers from losses due to wheat streak,” Fritz said.

The K-State team will plant field plots near Salina this year to make sure what they’re seeing in the greenhouse and lab holds true.

Another bit of good news for wheat growers is that preliminary data show that some Hessian fly resistance genes also have resistance to wheat curl mite damage.

The next step, Smith said, will be for Fritz’s group to determine the yield potential and quality of the grain in the new breeding line. That will likely take two to three years as the seed becomes available and is planted in various parts of the state.

“There are 300 different soil types in Kansas alone,” he said, adding that soil type is just one of many variables that affects how a wheat variety performs. Planting date, moisture and temperature through the crop year are among the many other variables.

“Our next and final step is to nail down resistance to the Triticum mosaic virus,” Smith said, adding that he’s optimistic the team will be successful, but that the odds of finding it in the lines with resistance to the mite and the other two viruses are reduced.

“It’s not unreasonable to think that in three or four years, we’ll have a new variety that is resistant to this mite and the diseases it carries,” Smith said.